Tool for removing insulation from electrical wires

ABSTRACT

A tool for removing insulation from an electric wire comprises a gas burner having secured thereto a stationary sheet metal member and is pivotally connected to another sheet metal member which latter has a manually operable handle. The members are provided near their ends with semicircular recesses which when said members are pivoted together constitute circular cutting edges. A cutting edge extending between said circular cutting edges and in a plane perpendicular thereto is also employed. The cutting edges are located at such a distance from the burner that the flame thereof will not damage the wire to be deinsulated nor heat said edge portions to a degree which makes the de-insulation possible when said burner is set to run with a reduced fuel saving flame.

United States Patent [1 1 Hammar [111 3,787,969 [451 Jan. 29, 1974 TOOL FOR REMOVING INSULATION FROM ELECTRICAL WIRES [76] Inventor: Algot P. Hammar, PO. Box 303,

Bjursas, Sweden [22] Filed: Feb. 14, 1972 [21] App]. No.: 226,049

[52] US. Cl 30/140, 30/90.], 81/95 R [51] Int. Cl H02g 1/12 [58] Field of Search.... 81/95 R, 9.5 B, 9.5 C, 9.5];

[56] References Cited UNITED STATES PATENTS 3,198,038 8/1965 Fleming 8l/9.5 R 3,293,956 l2/I966 Adamson et al 81/95 FOREIGN PATENTS OR APPLICATIONS 664,925 l/l952 Great Britain 81/951 Primary Examiner-Granville Y. Custer, .lr. Assistant Examiner-Roscoe V. Parker Attorney, Agent, or Firm-Linton & Linton [57,] ABSTRACT A tool for removing insulation from an electric wire comprises a gas burner having secured thereto a stationary sheet metal member and is pivotally connected to another sheet metal 'member which latter has a manually operable handle. The members are provided near their ends with semicircular recesses which when said members are pivoted together constitute circular cutting edges. A cutting edge extending between said circular cutting edges and in a plane perpendicular thereto is also employed. The cutting edges are located at such a distance from the burner that the flame thereof will not damage the wire to be deinsulated nor heat said edge portions to a degree which makes the de-insulation possible when said burner is set to run with a reduced fuel saving flame.

3 Claims, 3 Drawing Figures TOOL FOR REMOVING INSULATION FROM ELECTRICAL WIRES This invention refers to a tool for removing insulation from electrical cables having an outer cover of a plastic material or a material comparable therewith.

A really useful tool for this purpose has hitherto not been found. The suggested tools have been complicated and expensive, and yet not been able to eliminate the risk of damaging the electrical conductors. These deficients of the known tools have resulted in the supervising authorities recommending the use of conven tional knives for carrying out the insulation removal. Since the used plastic materials are-relatively hard and difficult to handle there is a very big demand for tools being really useful for removing insulations of the kind referred to.

As it is often desired to remove the insulation from only one of a plurality of wires, constituting a cable having a bundle of wires it is also necessary that the tool may be introduced in the small spaces between said wires that may be obtained by applying wedges between the separate wires. 4

Thus, the primary object of the present invention is to provide a new tool for removing insulations from cables, which overcomes the disadvantages referred to.

To accomplish this and other objects the invention has the characteristics disclosed in the following claims. 7

In the accompanying drawing an exemplary embodiment of the invention is illustrated, wherein 7 FIG. 1 is a perspective view of a preferred embodiment of the invention while FIG. 2 is also a perspectiveview on a bigger'scale of the functional members of the tool in cooperating position and I FIG. 3 is an end view of the members according to FIG. 2 during an insulation removal operation.

' The tool illustrated in the drawing comprises a heating source in the form ofa cylinder 1 containing a suitable combustible gas such as propane or butane and a burner 2 connected thereto with the supply of gas to said burner being controlled by a valve in a known manner. A bracket 5 is connected to the gas burner or the supply line thereof by a clamp 4 or the like. Said bracket may comprise a sheet material member having end parts being bent to lugs 6 to receive therebetweena pivot axis 7, which also extends through downwardly directed parts 8a, 8b being parallel to each other and located at a distance from each other with said parts belonging to an upper leg generally designated 9. Said upper leg has an upper operating means in the illustrated embodiment and a lower operating means 11 is provided in connection with the downwardly directed parts 8a, 8b to enable the convenient pivoting upwardly and downwardly of leg 9 about the axis 7. The end of leg 9 positioned opposite the operating means 10 has two downwardly directed sideparts 11a, 11b being located at a distance from each other, preferably being formed by bending the sheet material. Recesses 12a, 12b are provided in these parts with said recesses being downwardly open and defined by preferably semicircular surfaces. An opening 13 is preferably provided in the upper leg through which opening the flame of the burner may be observed. 7

The tool further comprises a lower leg, designated generally 14, said leg however being rigidly secured to the burner nozzle 2 for which purpose said lower leg has slots 15 in vertical portions 16a, 16!) thereof. Recesses 17a, 17!) are also adapted in said vertical portions, which recesses correspond to the previously mentioned recesses in the upper leg with the difference however, that the recesses 17a, 17b are upwardly open. The portion 18 between the portions 16a, 16b of the leg is obliquely bent upwardly and serves to incline the flame towards the upper leg. This latter has a downwardly directed bent portion 23. The lower edge of said portion 23 lies in the same level as the upper boundaries of the recesses 12a, 12!). This bent portion 23 as well as the recesses l2a, -l 2b will thereby together form a cutting edge, combined of two substantially semicircular cutting edges located at a distance from each other and positioned in planes being parallel to the longitudinal direction of the leg, and a straight cutting edge lying in a plane being parallel to the transverse direction of the leg. In the same manner the recesses 17a, 17b form corresponding semi-circular cutting edges. As seen in FIG. 2 the distance between the two vertical portions 11a, 11b of the upper leg is greater than the distance between the corresponding portions 16a, 16b of the lower leg, whereby the legs when assembled may guide each other in the side direction as seen in FIG. land 3.

The bent portion 18 is preferably located at a distance from the burner that somewhat exceeds the distance between said burner and the bent portion 23. Thus the flame when leaving portion 18 will pass along both sides of bent portion 23 thereby heating it effectively.

As seen in FIG. 2 and 3 the legs 9 and 14 are so located that in the pivoted down position thereof, when the legs are facing each other, the respective recesses therof are aligned in the transverse direction of the legs.

To be able to use a light weight gas cylinder this cylinder may be provided with a support which in FIG. 1 is designated generally by the reference numeral 19, and comprises container 20 being upwardly open and surrounding the cylinder 1 with said container being secured to a bottom plate 21.

The tool described above is working in the following manner; In case it is desired to remove a given length of insulation from a cable 22, said cable or wire thereof is insertedin the guiding groove formed by the recesses 12a, 12b, 17a, 17b after the legs in the cooperating position thereof have been heated by the gas flame and the upper leg subsequently has been pivoted upwardly and the flame has been reduced. When the upper leg is thereupon pivoted downwardly according to FIG. 2 the cutting edges defined by the respective recesses will provide a recess extending around the cover of the cable while the portion positioned between the free end of the cable and said recess will be cut in the longitudinal direction thereof. After the-leg is pivoted upwardly the portion of the outer cover of the cable that is cut away by a heat application may be easily removed by hand or by a pair of pliers. Thus, the only thing to be observed is that a cable portion be inserted so as to correspond to the desired length of the insulation to be, removed. From the foregoing it is to be understood that the removal of the insulation is not only possible at the end of a cable but may also be accomplished in any 10- cation on the same, whereby the length of the removed insulation corresponds to the distance between the surfaces 16a, 16b. The burner may suitably run on a flame of economic size between the insulation removing steps.

I claim:

1. An insulation removing tool comprising a heater of the flame generating type, a first sheet metal member being stationary relative to said heater and adapted to be heated thereby, said stationary member having generally semicircular laterally spaced cutting edges, and a second sheet metal member, being pivotally connected to said first member and provided with a manually operable handle and having also generally semicircular, laterally spaced cutting edges adapted to constitute together with the first mentioned edges two generally circular cutting edges, at least one of the members further having a cutting edge extending laterally intermediate the semicircular edges, all of said edge portions being located at such a distance from the heater that when the latter is set to run with a reduced flame said flame will not damage the wire to be tie-insulated nor heat said edge portions to a degree which makes the de-insulation possible.

2. An insulation removing tool as claimed in claim 1, the stationary as well as the pivotally adapted member having its ends bent to U-shape, the vertical flanges of said U-portions being provided with recesses constituting the generally semicircular cutting edges, said flanges of the first member preferably overlapping the flanges of the second member when said members are swung towards each other, the web of one of the members having an end portion extending at substantially a right angle to constitute the lateral cutting edge while the web of the other member has its end portion positioned to serve as a guide for directing the flame towards the lateral cutting edge.

3. An insulation removing tool as claimed in claim 2 said portion serving to guide the flame preferably being curved and being located at a distance from the flame front that somewhat exceeds that of the lateral cutting edge such that the flame when adjusted to head said lateral cutting edge and leaving said bent portion is split into two streams one stream at each side of said lateral cutting edge. 

1. An insulation removing tool comprising a heater of the flame generating type, a first sheet metal member being stationary relative to said heater and adapted to be heated thereby, said stationary member having generally semicircular laterally spaced cutting edges, and a second sheet metal member, being pivotally connected to said first member and provided with a manually operable handle and having also generally semicircular, laterally spaced cutting edges adapted to constitute together with the first mentioned edges two generally circular cutting edges, at least one of the members further having a cutting edge extending laterally intermediate the semicircular edges, all of said edge portions being located at such a distance from the heater that when the latter is set to run with a reduced flame said flame will not damage the wire to be de-insulated nor heat said edge portions to a degree which makes the de-insulation possible.
 2. An insulation removing tool as claimed in claim 1, the stationary as well as the pivotally adapted member having its ends bent to U-shape, the vertical flanges of said U-portions being provided with recesses constituting the generally semicircular cutting edges, said flanges of the first member preferably overlapping the flanges of the second member when said members are swung towards each other, the web of one of the members having an end portion extending at substantially a right angle to constitute the lateral cutting edge while the web of the other member has its end portion positioned to serve as a guide for directing the flame towards the lateral cutting edge.
 3. An insulation removing tool as claimed in claim 2 said portion serving to guide the flame preferably being curved and being located at a distance from the flame front that somewhat exceeds that of the lateral cutting edge such that the flame when adjusted to head said lateral cutting edge and leaving said bent portion is split into two streams one stream at each side of said lateral cutting edge. 